28071

Appears in sequences

• Numbers k such that sigma(k-3) + sigma(k+3) = sigma(2*k).at n=25A067129
• Expansion of (1-x) / (1+x^2+2*x^3).at n=31A078033
• Numbers k that divide the sum of the digits of k!!, the double factorial of k.at n=18A108858
• a(n) = A118443(n)/(n+1), where A118443 is the row sums of triangle A118441.at n=15A118444
• Numerator of imaginary part of (3*i - 1)^(-n).at n=15A124871
• Let f(k) = exp(Pi*sqrt(k)); sequence gives numbers k such that ceiling(f(k)) - f(k) < 1/10^3.at n=41A127022
• a(n) = 2*a(n-1) - 5*a(n-2), with a(1) = -1, a(2) = -7.at n=14A138749
• a(n) = 58*n^2 - 1.at n=21A158668
• Number of n X 4 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.at n=9A229441
• Integers of the form 8k+7 that can be written as a sum of four distinct squares of the form m, m+2, m+4, m+5, where m == 1 (mod 4).at n=20A243579
• Number of length 4+2 0..n arrays with some pair in every consecutive three terms totalling exactly n.at n=9A245873
• Triangle read by rows where T(n,k) is the number of chains of length k from minimum to maximum in the poset of integer partitions of n ordered by refinement.at n=60A330785